Mix semisweet chocolate, baking chocolate, and margarine together; melt carefully in microwave or over simmering water in double boiler. Allow to cool to lukewarm. Mix sour cream, sugar, corn syrup, egg and vanilla. Blend with melted chocolates. Blend flour, soda and salt; add the chocolate mixture and blend very well. Add the chocolate chips. Pour batter into 12 paper-lined or greased muffin tins. Bake in preheated 400-degree oven for about 20 minutes. Remove from muffin tins and allow to cool on wire racks.